Though normally confined to the Arctic, this polar vortex is catching everyone's attention because it has dipped so low into North America — plunging millions of Americans and Canadians into a deep freeze.

NOAA scientists have suggested that climate change may be responsible for a weakening of the polar vortex.

"The last five years have been the warmest recorded period in the Arctic and climate conditions over the Arctic cannot be ruled out as influencing weather in some sub-Arctic regions," NOAA noted.